The present invention relates to a ratchet drive wrench. More particularly, the invention is directed to a ratchet drive wrench having a handle-carried drive head in which a rotatable core is releasably secured.. The core includes an end shank or boss to which a selectable tool element such a socket may be releasably secured. The body of the core houses a shiftable pawl which couples the drive head to the core for rotation of the core, selectively, in each of opposed driving modes.
Ratchet wrenches of the general type to which the present disclosure is directed are known in the prior art. One such wrench is described in K. K. Chow U.S. Pat. application Ser. No. 07/017731, filed Feb. 24, 1987. The entire disclosure of that application is hereby incorporated herein by reference, to the extent it is not inconsistent herewith.
It has been established that in the usual or expected use of ratchet drive wrenches that foreign matter invades the interior of the wrenches and lodges in the zones of manipulative operation of the drive-mode-reversing pawl. The debris not only interferes with the effective operation of the drive wrench, but also contributes materially to deterioration of the working elements and to a shortening of the useful wrench life. It has been found that immersing or washing the tool head and core assembly in a cleansing fluid such as petroleum spirits may clean the wrench superficially but does not effectively remove the entrapped foreign material. Significant "solids" are retained in the tool assembly.
Notwithstanding such periodic "washing", the interior of the wrench retains abrasive solids. These act to accelerate deterioration of the wrench components including the toothed pawl and the cooperating pawl-engaging teeth of the drive ring.
Periodic partial disassembly of ratchet drive wrenches, to an extent of withdrawing and separating the core from the drive ring, followed by a rinsing of these elements in a liquid cleansing composition has been found to be a much more effective maintenance technique for insuring long-life and for retaining good operating capability for the ratchet drive wrenches. For the most part, however, ratchet wrenches can be disassembled only with the use of a tool and with some difficulty in a procedure which may be hazardous to the safety of the wrench user. For example, it is often necessary to employ a prying tool to extracate the locking snap ring or spring band from a groove or channel in which the spring is seated. In other common arrangements one or more locking screws or bolts must be removed before disassembly is possible.
Some ratchet wrenches embody structures which do permit a useful partial disassembly, without the use of tools. Several such wrenches are described in the above referred to K. K. Chow U.S. patent application Ser. No. 07/017731.
The wrench structures there shown allow removal of the core from the drive ring manually, without the use of tools. To this extent the structures obviate certain objectionable features of a majority of prior art devices. Each does, however, require the physical displacement of an internal locking ring, and, or interlocking keying element. Each utilizes outwardly projecting pin or button or shaft.
While the referred to prior art structures are suitable for their intended purpose, to some extent at least, each wrench is subject to or susceptible of a possible inadvertent or unintended actuation of the core releasing mechanism. It is an aim of the present invention to provide in a tool of the general class described exceedingly simple yet highly stable, effective and reliable core-release mechanism which functions without the use of tools, which cannot be activated by accident, which effects a release of the drive-ring-held core, but only under positive and intentional manipulative action, and which oviates other shortcomings of prior art ratchet drive tools.